Five people are charged in the investigation into the death of Matthew Perry.

LOS ANGELES (AP) — Five people, including his personal assistant and two doctors, have been charged in connection with Matthew Perry's The perpetrator's death was the result of a “wide-ranging underground criminal network” which, according to prosecutors, had set itself the goal of providing the “Friends” star with the powerful anesthetic that killed him.

Doctors took advantage of Perry's history of addiction in the final months of his life last year to administer ketamine to him in amounts they knew were dangerous, U.S. Attorney Martin Estrada said when he announced the charges on Thursday.

“They knew what they were doing was wrong,” Estrada said. “They knew they were putting Mr. Perry in great danger. But they did it anyway.”

One doctor even wrote in a text message: “I wonder how much this idiot is going to pay” and “Let's find out,” according to an indictment unsealed Thursday.

Perry died of a ketamine overdose in October. Prosecutors said he received multiple injections the day of his death from his personal assistant, Kenneth Iwamasa, who lived with him. Iwamasa found Perry dead later that day and was the first to speak to investigators.

Ketamine has seen a huge increase in use in recent years as a treatment for depression, anxiety and pain. Although the drug is not approved for these conditions, doctors can prescribe it for what are known as off-label uses.

Perry had received regular ketamine infusions for depression from his primary care doctors, who were not among the defendants – but in quantities far from sufficient to explain his death – authorities said.

When these doctors gave him no further treatment, he turned to others in desperation.

“We're not talking about legitimate ketamine treatment here,” Estrada said. “We're talking about two doctors who abused the trust they had and abused their license to put another human being's life at risk.”

DEA Director Anne Milgram said in one case the actor paid $2,000 for a vial of ketamine that cost one of the doctors about $12. Perry paid doctors about $55,000 in cash in the two months before his death, Estrada said.

Two of the people, including one of the accused doctors, were arrested on Thursday, Estrada said. Two of the defendants, including Iwamasa, have already pleaded guilty and a third person has agreed to plead guilty.

Numerous messages requesting a statement from the lawyers or law firms of all defendants have so far received no response.

Among those arrested Thursday is Dr. Salvador Plasencia, who faces seven counts of ketamine trafficking and two charges related to allegations that he falsified records following Perry's death.

Plasencia appeared briefly in court Thursday afternoon and pleaded not guilty. He can be released on $100,000 bail.

Plasencia's attorney, Stefan Sacks, asked that his client be allowed to continue treating patients in his practice after his release. He said he had already surrendered his DEA license to prescribe dangerous drugs and that the Perry case was “isolated.”

Assistant U.S. Attorney Ian V. Yanniello objected, saying Plasencia “acted essentially like a street drug dealer.”

Judge Alka Sagar ruled that Plasencia could only treat patients if they signed a document stating that they had been informed of the allegations against him.

The other person arrested Thursday is Jasveen Sangha, whom prosecutors described as a drug trafficker who was known to her customers as the “ketamine queen.” Ketamine supplied by Sangha was the cause of Perry's death, authorities said.

If convicted, Plasencia could face up to 120 years in prison, prosecutors said. Sangha could receive a life sentence.

According to records, Plasencia's medical license is in good standing and has no complaints, although it expires in October.

A San Diego doctor, Dr. Mark Chavez, has pleaded guilty to conspiracy to distribute ketamine. Prosecutors allege Chavez passed ketamine to Plasencia and obtained some of the drug through a forged prescription from a wholesaler.

The prosecutor said the defendants exchanged messages shortly after Perry's death citing ketamine as the cause of death. Estrada said they deleted messages and falsified medical records to cover up their involvement.

Los Angeles police said in May that they are working with the US Drug Enforcement Agency and the US Postal Inspection Service to investigate why the 54-year-old had so much of the surgical anesthetic in his body.

Iwamasa found the actor face down in his hot tub on October 28, and paramedics who were called to the scene immediately pronounced him dead.

The assistant obtained the ketamine from Erik Fleming, who pleaded guilty to obtaining the drug from Sangha and supplying it to Iwamasa. In total, he supplied 50 vials of ketamine to Perry, including 25 four days before the actor's death.

Perry’s autopsy, released in December, revealed that the amount of ketamine in his blood was within the range used for general anesthesia during surgery.

But his last proper treatment was 1 1/2 weeks ago, the coroner said, and the drug is normally broken down within hours.

Estrada said Plasencia saw Perry freeze and his blood pressure skyrocket after injecting him with the drug, but still left several vials with Iwamura for the actor to inject later.

The medical examiner listed ketamine as the primary cause of death. The death was ruled an accident, with no foul play suspected, the report said. Drowning and other medical problems were contributing factors, the medical examiner said.

Perry had for years struggles with addiction This goes back to his time on “Friends,” when he became one of the biggest television stars of his generation as Chandler Bing alongside Jennifer Aniston, Courteney Cox, Lisa Kudrow, Matt LeBlanc and David Schwimmer for 10 seasons from 1994 to 2004. NBC's megahit sitcom.

In other cases, drug-related deaths of celebrities have led authorities to prosecute drug traffickers.

After Rapper Mac Millerdied of an overdose of cocaine, alcohol and counterfeit oxycodone containing fentanyl, Two of the men who gave him the fentanyl were convicted of distributing the drugOne was sentenced to more than 17 years in a federal prison, the other to 10 years.

And then MichaelJackson died in 2009 from a lethal dose of propofol, a drug intended only for use during surgeries and other medical procedures, not for the insomnia for which the singer sought it, his doctor said. Conrad Murraywas convicted of manslaughter in 2011. Murray continues to maintain his innocence.

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Writer Michael Balsamo contributed from New York.